This invention relates to an apparatus and method for bag making, filling, and sealing, which removes entrained air from a filled or partially filled bag.
In applications where it is necessary to package a quantity of articles within a sealed bag, vertical form, fill and seal bagging machines are well known and widely employed in the art. An example of such a machine is disclosed in U.S. Pat. No. 4,697,403 to Simpson et al. Packaging of this nature usually involves dispensing the product material into a bag and thereafter sealing the bag. If not extracted before the sealing process is complete, undesirable quantities of air will remain within the bag after it has been sealed. The excess air which remains in the package after sealing is often problematic, and can occupy a substantial portion of the volume of the shipping case in which the bags are transported. During the course of shipping, the excess air may bleed out of the filled bags, thereby creating an unoccupied volume within the shipping case. When this occurs the bags containing product articles are no longer supported as well by the case, and are therefore free to move about, the result of which is often damage to the articles. In addition to minimizing product damage, the removal of excess air from a package prior to sealing greatly facilitates the number of product bags which can occupy the shipping case volume.
The prior art has attempted to deal with the removal of excess air from packages largely by providing a vacuum means for withdrawing air from a package, such as is disclosed in U.S. Pat. No. 3,545,983 issued to Q. T. Woods. The Woods patent discloses a vacuum chamber in combination with shaping plates for reducing the oxygen content of a package prior to sealing. Often the high speed with which today's packaging machines operate does not make withdrawal of air by known vacuum methods feasible, since such methods require that tubes be inserted into the package or that the package be enclosed within a chamber prior to sealing.
Other attempts by bagging machine manufacturers to provide a means for expelling air from packages by using foam or spring deflators have been used, such as, for example, U.S. Pat. No. 3,471,990 to J. A. Bonuchi et al. which discloses the use of a foam member to compress a package in order to remove excess air. Foam, however, is often susceptible to compressing or freying within a short period of use, thereby necessitating that production be interrupted in order to change the foam. Another Patent, U.S. Pat. No. 4,633,654, teaches placing each package in a sealed environment in order to remove the excess air therefrom. Aside from it being more difficult to maintain a sealed environment, such can also be costly.
The present invention provides a novel form, fill and packaging machine which will expel air from a package before sealing, while alleviating problems encountered by prior methods and apparatus.